Frequency agile telemetry system for implantable medical device

ABSTRACT

A system enables high-frequency communication between an external communication device and one or more implantable medical devices. The system implements a communication protocol in which the external communication device interrogates any implantable medical devices within range to establish one-to-one communication links for purposes of exchanging data and/or programming the medical devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/833,596, filed Apr. 27, 2004, now U.S. Pat. No. 7,177,700, issued onFeb. 13, 2007, which is a continuation of U.S. patent application Ser.No. 10/001,225, filed Nov. 2, 2001, and now U.S. Pat. No. 6,763,269,issued Jul. 13, 2004.

TECHNICAL FIELD

The present invention generally relates to implantable medical devices.

BACKGROUND

There are many kinds of implantable medical devices. Some monitorpatient conditions while others disperse some form of therapy. Oneparticular type of implantable medical device is an implantable cardiactherapy device, or ICTD. ICTDs are implanted within the body of apatient to monitor, regulate, and/or correct heart activity. ICTDsinclude implantable cardiac stimulation devices (e.g., implantablecardiac pacemakers, implantable defibrillators) that apply stimulationtherapy to the heart as well as implantable cardiac monitors thatmonitor heart activity.

ICTDs typically include a control unit positioned within a casing thatis implanted into the body and a set of leads that are positioned toimpart stimulation and/or monitor cardiac activity. With improvedprocessor and memory technologies, the control units have becomeincreasingly more sophisticated, allowing them to monitor many types ofconditions and apply tailored stimulation therapies in response to thoseconditions.

ICTDs are typically capable of being programmed remotely by an externalprogramming device, often called a “programmer”. Today, individual ICTDsare equipped with telemetry circuits that communicate with theprogrammer. One type of programmer utilizes an electromagnetic wand thatis placed near the implanted cardiac device to communicate with theimplanted device. The wand contains a coil that forms a transformercoupling with the ICTD telemetry circuitry. The wand transmits lowfrequency signals by varying the current in a coil.

Early telemetry systems were passive, meaning that the communication wasunidirectional from the programmer to the implanted device. Passivetelemetry allowed a treating physician to download instructions to theimplanted device following implantation. Due to power and sizeconstraints, early commercial versions of the implanted devices wereincapable of transmitting information back to the programmer.

As power capabilities improved, active telemetry became feasible,allowing synchronous bi-directional communication between the implanteddevice and the programmer. Active telemetry utilizes a half-duplexcommunication mode in which the programmer sends instructions in apredefined frame format and, following termination of this transmission,the implanted device returns data using the frame format. With activetelemetry, the treating physician is able to not only program theimplanted device, but also retrieve information from the implanteddevice to evaluate heart activity and device performance. The treatingphysician may periodically want to review device performance or heartactivity data for predefined periods of time to ensure that the deviceis providing therapy in desired manner. Consequently, current generationimplantable cardiac therapy devices incorporate memories, and theprocessors periodically sample and record various performance parametermeasurements in the memories.

Current telemetry systems have a limited communication range between theprogrammer wand and the ICTD, which is often referred to as “short-rangetelemetry” or “wand telemetry”. For effective communication, the wand isheld within two feet of the ICTD, and typically within several inches.One problem is that the ICTD has insufficient power to transmit longerrange signals. Another consideration is the inherent EMI-resistantdesign of the ICTD. The ICTD circuitry is typically housed in ahermetically shielded can to prevent electromagnetic interference (EMI)from disrupting operation. The can prevents penetration of highfrequencies, thereby limiting communication to the low frequency rangeof less than 200 KHz. In one exemplary system, signals sent from theprogrammer to the implanted device are transmitted on a carrier ofapproximately 36 KHz, and data is transmitted to and from the implanteddevice at approximately 8 KBaud.

Conventionally, data about a patient's cardiac condition is gathered andstored by the programmer during programming sessions of the ICTDs.Analysis of the cardiac condition is performed locally by theprogramming software. Programmers offer comprehensive diagnosticcapabilities, high-speed processing, and easy operation, therebyfacilitating efficient programming and timely patient follow-up.

In addition to local analysis, TransTelephonic Monitoring (TTM) systemsare employed to gather current cardiac data of patients when the patientis remote from the healthcare provider. TTM systems are placed inpatients' homes. They typically include a base unit that gathersinformation from the ICTD much like the programmer would. The base unitis connected to a telephone line so that data may be transmitted to themedical staff responsible for that patient. An example of an ICTD TTMsystem is a service from St. Jude Medical® and Raytel® Cardiac Servicescalled “Housecall™.” This service provides current programmed parametersand episode diagnostic information for a plurality of events includingstored electrograms (EGMs). Real-time EGMs with annotated statusinformation can also be transmitted.

Using a telephone and a transmitter, the TTM system provides both themedical staff and the patient the convenience of instant analysis oftherapy without having the patient leave the comfort of home. Typically,real-time measurements are transmitted in just minutes. Patients may beclosely monitored, and the medical staff has more control of theirpatient's treatment, thus administering better patient management.

While strides have been made for improving patient monitoring, thereremains an ongoing need to improve the communication capabilitiesbetween implanted devices and external devices, particularly the need tocommunicate more effectively over greater transmissions ranges.

SUMMARY

A system enables high-frequency communication between an externalcommunication device and one or more implantable medical devices. Thesystem implements a communication protocol in which the externalcommunication device interrogates any implantable medical devices withinrange to establish one-to-one communication links for purposes ofexchanging data and/or programming the medical devices.

In one implementation, the external communication device transmits aninterrogation signal on one or more frequencies within a first set offrequencies. The interrogation signal serves as an invitation tocommunicate with the implantable medical device. The implantable medicaldevice listens for the interrogation signal at a frequency within thefirst set of frequencies. Upon receipt, the implantable medical devicetransmits a reply on a second frequency selected from a second set offrequencies. The first and second set of frequencies may overlap or bemutually exclusive. The external communication device monitors thesecond set of frequencies for the reply. Upon receipt of the reply, theexternal communication device assigns a communication channel to theimplantable medical device for purposes of continuing communication. Forthat point, the devices can frequency hop among multiple channels morethan once during communication of information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of a network architecture with anexemplary implantable medical device connected to a network of computingsystems used by various knowledge workers. The implantable medicaldevice is depicted and described in the context of an implantablecardiac therapy device (ICTD).

FIG. 2 is a functional diagram illustrating information flow from theICTD to the computing systems associated with the knowledge workers.

FIG. 3 is a functional diagram illustrating how the various computingsystems share pieces of information to improve care given to thepatient.

FIG. 4 is a functional diagram illustrating information flow from thecomputing systems back to the ICTD.

FIG. 5 is a simplified illustration of an ICTD in electricalcommunication with a patient's heart for monitoring heart activityand/or delivering stimulation therapy.

FIG. 6 is a functional block diagram of an exemplary implantable cardiactherapy device.

FIG. 7 is a functional block diagram of an exemplary computing devicethat may be used in the computing systems of the cardiac therapy networkarchitecture.

FIG. 8 is a function block diagram of the ICTD and an externalcommunication device to illustrate how the ICTD and communication deviceestablish a communication link.

FIG. 9 is a flow diagram of a method for establishing a communicationlink between the ICTD and the external communication device.

FIG. 10 is a diagrammatic illustration of a system with multiple ICTDscommunicating with a common external communication device.

FIG. 11 is a diagrammatic illustration of an ICTD with packaging thatdefines dual isolated chambers, one for housing high-frequency circuitryand a second for housing the ICTD monitoring and stimulation circuitry.

In the description that follows, like numerals or reference designatorsare used to reference like parts or elements.

DETAILED DESCRIPTION

The following discussion unfolds in the context of an implantablecardiac therapy device (ICTD) linked to a networked system of computingsystems. It is noted that the ICTD is just one exemplary type ofimplantable medical device. Other types of implantable medical devicesmay be employed, such as implantable medicine dispensers, implantablenerve stimulators, and so on.

Cardiac Therapy Network

FIG. 1 shows an exemplary cardiac therapy network architecture 100 thatincludes an implantable medical device in the form of an implantablecardiac therapy device (ICTD) 102. The ICTD 102 is coupled to a networkof computing systems associated with various knowledge workers who haveinterest in cardiac therapy. The ICTD is illustrated as being implantedin a human patient 104. The ICTD 102 is in electrical communication witha patient's heart 106 by way of multiple leads 108 suitable formonitoring cardiac activity and/or delivering multi-chamber stimulationand shock therapy.

The ICTD 102 may communicate with a standalone or offline programmer 110via short-range telemetry technology. The offline programmer 110 isequipped with a wand that, when positioned proximal to the ICTD 102,communicates with the ICTD 102 through a magnetic coupling.

The ICTD 102 can alternatively, or additionally, communicate with alocal transceiver 112. The local transceiver 112 may be a device thatresides on or near the patient, such as an electronic communicationsdevice that is worn by the patient or is situated on a structure withinthe room or residence of the patient. The local transceiver 112communicates with the ICTD 102 using short-range telemetry orlonger-range high-frequency-based telemetry, such as RF (radiofrequency) transmissions. Alternatively, the local transceiver 112 maybe incorporated into the ICTD 102, as represented by dashed line 111. Inthis case, the ICTD includes a separate and isolated package area thataccommodates high-frequency transmissions without disrupting operationof the monitoring and stimulation circuitry.

Depending upon the implementation and transmission range, the localtransceiver 112 can be in communication with various other devices ofthe network architecture 100. One possible implementation is for thelocal transceiver 112 to transmit information received from the ICTD 102to a networked programmer 114, which is connected to network 120. Thenetworked programmer 114 is similar in operation to standaloneprogrammer 110, but differs in that it is connected to the network 120.The networked programmer 114 may be local to, or remote from, the localtransceiver 112; or alternatively, the local transceiver 112 may beincorporated into the networked programmer 114, as represented by dashedline 116.

Another possible implementation is for the local transceiver to beconnected directly to the network 120 for communication with remotecomputing devices and/or programmers. Still another possibility is forthe local transceiver 112 to communicate with the network 120 viawireless communication, such as via a satellite system 122.

The network 120 may be implemented by one or more different types ofnetworks (e.g., Internet, local area network, wide area network,telephone, cable, satellite, etc.), including wire-based technologies(e.g., telephone line, cable, fiber optics, etc.) and/or wirelesstechnologies (e.g., RF, cellular, microwave, IR, wireless personal areanetwork, etc.). The network 120 can be configured to support any numberof different protocols, including HTTP (HyperText Transport Protocol),TCP/IP (Transmission Control Protocol/Internet Protocol), WAP (WirelessApplication Protocol), IEEE 802.11, Bluetooth, and so on.

A number of knowledge workers are interested in data gathered from theimplantable cardiac therapy device 102. Representative knowledge workersinclude healthcare providers 130, the device manufacturer 132, clinicalgroups 134, and regulatory agencies 136. The knowledge workers areinterested in different portions of the data. For instance, thehealthcare providers 130 are interested in information pertaining to aparticular patient's condition. The manufacturer 132 cares about how thedevice is operating. The clinical groups 134 want certain data forinclusion in patient populations that can be studied and analyzed. Theregulatory agencies 136 are concerned whether the devices, and varioustreatments administered by them, are safe or pose a health risk.

The network architecture 100 facilitates distribution of the device datato the various knowledge workers. Information gathered from the deviceis integrated, processed, and distributed to the knowledge workers.Computer systems maintain and store the device data, and prepare thedata for efficient presentation to the knowledge workers. The computersystems are represented pictorially in FIG. 1 as databases. However,such systems can be implemented using a wide variety of computingdevices, ranging from small handheld computers or portable digitalassistants (PDAs) carried by physicians to workstations or mainframecomputers with large storage capabilities. The healthcare providers 130are equipped with computer systems 140 that store and process patientrecords 142. The manufacturer 132 has a computer system 144 that tracksdevice data 146 returned from ICTDs 102. The clinical groups 134 havecomputer systems 148 that store and analyze data across patientpopulations, as represented by a histogram 150. The regulatory agencies136 maintain computer systems 152 that register and track healthcarerisk data 154 for ICTDs.

The network architecture 100 supports two-way communication. Not only isdata collected from the ICTD 102 and distributed to the various computersystems of the knowledge workers, but also information can be returnedfrom these computer systems to the networked programmer 114 and/or thelocal transceiver 112 for communication back to the ICTD 102.Information returned to the ICTD 102 may be used to adjust operation ofthe device, or modify therapies being applied by the device. Suchinformation may be imparted to the ICTD 102 automatically, without thepatient's knowledge.

Additionally, information may be sent to a patient notification device160 to notify the patient of some event or item. The patientnotification device 160 can be implemented in a number of waysincluding, for example, as a telephone, a cellular phone, a pager, a PDA(personal digital assistant), a dedicated patient communication device,a computer, an alarm, and so on. Notifications may be as simple as aninstruction to sound an alarm to inform the patient to call into thehealthcare providers, or as complex as HTML-based pages with graphicsand textual data to educate the patient. Notification messages sent tothe patient notification device 160 can contain essentially any type ofinformation related to cardiac medicinal purposes or device operation.Such information might include new studies released by clinical groupspertaining to device operation and patient activity (e.g., habits,diets, exercise, etc.), recall notices or operational data from themanufacturer, patient-specific instructions sent by the healthcareproviders, or warnings published by regulatory groups.

Notifications can be sent directly from the knowledge worker to thepatient. Additionally, the network architecture 100 may include anotification system 170 that operates computer systems 172 designed tocreate and deliver notification messages 174 on behalf of the knowledgeworkers. The notification system 170 delivers the messages in formatssupported by the various types of patient notification devices 160. Forinstance, if the patient carries a pager, a notification message mightconsist of a simple text statement in a pager protocol. For a moresophisticated wireless-enabled PDA or Internet-oriented cellular phone,messages might contain more than text data and be formatted using WAPformats.

FIG. 2 shows the flow of data from the implantable cardiac therapydevice 102 to the various computer systems used by the knowledgeworkers. Data from the ICTD is output as digital data, as represented bythe string of 0's and 1's. The data may consist of any number of items,including heart activity (e.g., ECG), patient information, deviceoperation, analysis results from on-device diagnostics, and so on.

A data integrator 200 accumulates the data and stores it in a repository202. A processing system 204 processes portions of the data according tovarious applications 206 that are specifically tailored to place thedata into condition for various knowledge workers. For example,healthcare workers might be interested in certain portions of the data,such as the ECG data and the patient information. Clinical scientistsmight be interested in the heart data, but do not wish to see anypatient information. Manufacturers may be interested in the raw datastream itself as a tool to discern how the device is operating.Depending on the needs of the end worker, the processing system 204takes the raw device data, evaluates its accuracy and completeness, andgenerates different packages of data for delivery to the variousknowledge workers. The processed data packages are also stored in therepository 202.

When the data is ready for delivery, a distribution/presentation system208 distributes the different packages to the appropriate computersystems 140, 144, 148, 152, and 172. The distribution/presentationsystem 208 is configured to serve the packages according to theprotocols and formats desired by the computer systems. In this manner,the network architecture 100 allows relevant portions of device data,collected from the ICTD, to be disseminated to the appropriate knowledgeworkers in a form they prefer.

Once the ICTD data is delivered, the computer systems 140, 144, 148,152, and 172 store the data and/or present the data to the knowledgeworker. The computer systems may perform further processing specific totheir use of the data. Through these processes, the knowledge workerscreate additional information that is useful to the patient, or otherknowledge workers with interests in ICTDs. For example, from the ICTDdata, the knowledge workers might devise improved therapies for a givenpatient, or create instructions to modify operation of a specific ICTD,or gain a better understanding of how implantable cardiac devicesoperate in general, or develop better technologies for futuregenerations of ICTDs. Much of this created knowledge can be shared amongthe various knowledge workers.

FIG. 3 shows how the various computing systems 140, 144, 148, 152, and172 can cooperate and share pieces of information to improve the caregiven to a patient. Where appropriate and legally acceptable, thecomputer systems may be configured to pass non-private information amongthe various knowledge workers to better improve their understanding ofthe implantable medical field. Clinical results 150 produced by theclinical computer systems 148 may be shared with healthcare providers toimprove patient care or with manufacturers to help in their design ofnext generation devices. The sharing of information may further lead tobetter and timelier healthcare for the patients.

If the collective knowledge base produces information that may provehelpful to the patient, that information can be passed to thenotification system 172 for delivery to one or more patients. Also, anyone of the knowledge workers may wish to employ the notification system172 to send messages to the patient(s).

FIG. 4 shows, in more detail, the flow of information back from thevarious computer systems used by the knowledge workers to theimplantable cardiac therapy device 102 or the patient notificationdevice 160. Information from any one of the computing systems—healthcarecomputer system(s) 140, manufacturer computer system(s) 144, clinicalcomputer system(s) 148, regulatory computer system(s) 152—or thenotification system 172 can be sent to a patient feedback system 400.The patient feedback system 400 facilitates delivery of the informationback to the patient. It may be an independent system, or incorporatedinto one or more of the computing systems. It may alternatively beintegrated into the notification system 172.

The patient feedback system 400 may be implemented in many ways. As oneexemplary implementation, the patient feedback system 400 is implementedas a server that serves content back to the networked programmer 114,which then uses the information to program the ICTD 102 through a builtin transceiver 116, local transceiver 112, or wand-based telemetry. Asanother possible implementation, the patient feedback system may be acellular or RF transmission system that sends information back to thepatient feedback device 160.

The network architecture 100 facilitates continuous care around theclock, regardless of where the patient is located. For instance, supposethe patient is driving in the car when a cardiac episode occurs. TheICTD 102 detects the condition and transmits an alert message about thecondition to the local transceiver 112. The message is processed anddelivered to a physician's computer or PDA via the network 120. Thephysician can make a diagnosis and send some instructions back to thepatient's ICTD. The physician might also have a notification messagethat guides the patient to a nearest healthcare facility for furthertreatment sent via the notification system 170 to the patient'snotification device 160. Concurrently, the physician can share thepatient's records online with an attending physician at the healthcarefacility so that the attending physician can review the records prior tothe patient's arrival.

Exemplary ICTD

FIG. 5 shows an exemplary ICTD 102 in electrical communication with apatient's heart 106 for monitoring heart activity and/or deliveringstimulation therapy, such as pacing or defibrillation therapies. TheICTD 102 is in electrical communication with a patient's heart 106 byway of three leads 108(1)-(3). To sense atrial cardiac signals and toprovide right atrial chamber stimulation therapy, the ICTD 102 iscoupled to an implantable right atrial lead 108(1) having at least anatrial tip electrode 502, which typically is implanted in the patient'sright atrial appendage. To sense left atrial and ventricular cardiacsignals and to provide left chamber pacing therapy, the ICTD 102 iscoupled to a coronary sinus lead 108(2) designed for placement in thecoronary sinus region via the coronary sinus. The coronary sinus lead108(2) positions a distal electrode adjacent to the left ventricleand/or additional electrode(s) adjacent to the left atrium. An exemplarycoronary sinus lead 108(2) is designed to receive atrial and ventricularcardiac signals and to deliver left ventricular pacing therapy using atleast a left ventricular tip electrode 504, left atrial pacing therapyusing at least a left atrial ring electrode 506, and shocking therapyusing at least a left atrial coil electrode 508.

The ICTD 102 is also shown in electrical communication with thepatient's heart 106 by way of an implantable right ventricular lead108(3) having, in this implementation, a right ventricular tip electrode510, a right ventricular ring electrode 512, a right ventricular (RV)coil electrode 514, and an SVC coil electrode 516. Typically, the rightventricular lead 108(3) is transvenously inserted into the heart 102 toplace the right ventricular tip electrode 510 in the right ventricularapex so that the RV coil electrode 514 will be positioned in the rightventricle and the SVC coil electrode 516 will be positioned in thesuperior vena cava. Accordingly, the right ventricular lead 108(3) iscapable of receiving cardiac signals, and delivering stimulation in theform of pacing and shock therapy to the right ventricle.

FIG. 6 shows an exemplary, simplified block diagram depicting variouscomponents of the ICTD 102. The ICTD 102 can be configured to performone or more of a variety of functions including, for example, monitoringheart activity, monitoring patient activity, and treating fast and slowarrhythmias with stimulation therapy that includes cardioversion,defibrillation, and pacing stimulation. While a particular multi-chamberdevice is shown, it is to be appreciated and understood that this isdone for illustration purposes.

The circuitry is housed in housing 600, which is often referred to asthe “can”, “case”, “encasing”, or “case electrode”, and may beprogrammably selected to act as the return electrode for unipolar modes.Housing 600 may further be used as a return electrode alone or incombination with one or more of the coil electrodes for shockingpurposes. Housing 600 further includes a connector (not shown) having aplurality of terminals 602, 604, 606, 608, 612, 614, 616, and 618 (shownschematically and, for convenience, the names of the electrodes to whichthey are connected are shown next to the terminals).

To achieve right atrial sensing and pacing, the connector includes atleast a right atrial tip terminal (A_(R) TIP) 602 adapted for connectionto the atrial tip electrode 502. To achieve left chamber sensing,pacing, and shocking, the connector includes at least a left ventriculartip terminal (V_(L) TIP) 604, a left atrial ring terminal (A_(L) RING)606, and a left atrial shocking terminal (A_(L) COIL) 608, which areadapted for connection to the left ventricular ring electrode 504, theleft atrial ring electrode 506, and the left atrial coil electrode 508,respectively. To support right chamber sensing, pacing, and shocking,the connector includes a right ventricular tip terminal (V_(R) TIP) 612,a right ventricular ring terminal (V_(R) RING) 614, a right ventricularshocking terminal (RV COIL) 616, and an SVC shocking terminal (SVC COIL)618, which are adapted for connection to the right ventricular tipelectrode 510, right ventricular ring electrode 512, the RV coilelectrode 514, and the SVC coil electrode 516, respectively.

At the core of the ICTD 102 is a programmable microcontroller 620 thatcontrols various operations of the ICTD, including cardiac monitoringand stimulation therapy. Microcontroller 620 includes a microprocessor(or equivalent control circuitry), RAM and/or ROM memory, logic andtiming circuitry, state machine circuitry, and I/O circuitry.Microcontroller 620 includes the ability to process or monitor inputsignals (data) as controlled by a program code stored in a designatedblock of memory. Any suitable microcontroller 620 may be used. The useof microprocessor-based control circuits for performing timing and dataanalysis functions are well known in the art.

For discussion purposes, microcontroller 620 is illustrated as includingtiming control circuitry 632 to control the timing of the stimulationpulses (e.g., pacing rate, atrio-ventricular (AV) delay, atrialinterconduction (A-A) delay, or ventricular interconduction (V-V) delay,etc.) as well as to keep track of the timing of refractory periods,blanking intervals, noise detection windows, evoked response windows,alert intervals, marker channel timing, and so on. Microcontroller 220may further include various types of cardiac condition detectors 634(e.g., an arrhythmia detector, a morphology detector, etc.) and varioustypes of compensators 636 (e.g., orthostatic compensator, syncoperesponse module, etc.). These components can be utilized by the device102 for determining desirable times to administer various therapies. Thecomponents 632-636 may be implemented in hardware as part of themicrocontroller 620, or as software/firmware instructions programmedinto the device and executed on the microcontroller 620 during certainmodes of operation.

The ICTD 102 further includes an atrial pulse generator 622 and aventricular pulse generator 624 that generate pacing stimulation pulsesfor delivery by the right atrial lead 108(1), the coronary sinus lead108(2), and/or the right ventricular lead 108(3) via an electrodeconfiguration switch 626. It is understood that in order to providestimulation therapy in each of the four chambers of the heart, theatrial and ventricular pulse generators, 622 and 624, may includededicated, independent pulse generators, multiplexed pulse generators,or shared pulse generators. The pulse generators 622 and 624 arecontrolled by the microcontroller 620 via appropriate control signals628 and 630, respectively, to trigger or inhibit the stimulation pulses.

The electronic configuration switch 626 includes a plurality of switchesfor connecting the desired electrodes to the appropriate I/O circuits,thereby providing complete electrode programmability. Accordingly,switch 626, in response to a control signal 642 from the microcontroller620, determines the polarity of the stimulation pulses (e.g., unipolar,bipolar, combipolar, etc.) by selectively closing the appropriatecombination of switches (not shown).

Atrial sensing circuits 644 and ventricular sensing circuits 646 mayalso be selectively coupled to the right atrial lead 108(1), coronarysinus lead 108(2), and the right ventricular lead 108(3), through theswitch 626 to detect the presence of cardiac activity in each of thefour chambers of the heart. Accordingly, the atrial (ATR. SENSE) andventricular (VTR. SENSE) sensing circuits, 644 and 646, may includededicated sense amplifiers, multiplexed amplifiers, or sharedamplifiers. Each sensing circuit 644 and 646 may further employ one ormore low power, precision amplifiers with programmable gain and/orautomatic gain control, bandpass filtering, and a threshold detectioncircuit to selectively sense the cardiac signal of interest. Theautomatic gain control enables the ICTD 102 to deal effectively with thedifficult problem of sensing the low amplitude signal characteristics ofatrial or ventricular fibrillation. Switch 626 determines the “sensingpolarity” of the cardiac signal by selectively closing the appropriateswitches. In this way, the clinician may program the sensing polarityindependent of the stimulation polarity.

The outputs of the atrial and ventricular sensing circuits 644 and 646are connected to the microcontroller 620 which, in turn, is able totrigger or inhibit the atrial and ventricular pulse generators 622 and624, respectively, in a demand fashion in response to the absence orpresence of cardiac activity in the appropriate chambers of the heart.The sensing circuits 644 and 646 receive control signals over signallines 648 and 650 from the microcontroller 620 for purposes ofcontrolling the gain, threshold, polarization charge removal circuitry(not shown), and the timing of any blocking circuitry (not shown)coupled to the inputs of the sensing circuits 644 and 646.

Cardiac signals are also applied to inputs of an analog-to-digital (ND)data acquisition system 652. The data acquisition system 652 isconfigured to acquire intracardiac electrogram signals, convert the rawanalog data into a digital signal, and store the digital signals forlater processing and/or telemetric transmission to an external device654. The data acquisition system 652 is coupled to the right atrial lead108(1), the coronary sinus lead 108(2), and the right ventricular lead108(3) through the switch 626 to sample cardiac signals across any pairof desired electrodes.

The data acquisition system 652 may be coupled to the microcontroller620, or other detection circuitry, to detect an evoked response from theheart 106 in response to an applied stimulus, thereby aiding in thedetection of “capture”. Capture occurs when an electrical stimulusapplied to the heart is of sufficient energy to depolarize the cardiactissue, thereby causing the heart muscle to contract. Themicrocontroller 620 detects a depolarization signal during a windowfollowing a stimulation pulse, the presence of which indicates thatcapture has occurred. The microcontroller 620 enables capture detectionby triggering the ventricular pulse generator 624 to generate astimulation pulse, starting a capture detection window using the timingcontrol circuitry 632 within the microcontroller 620, and enabling thedata acquisition system 652 via control signal 656 to sample the cardiacsignal that falls in the capture detection window and, based on theamplitude, determines if capture has occurred.

The microcontroller 620 is further coupled to a memory 660 by a suitabledata/address bus 662, wherein the programmable operating parameters usedby the microcontroller 620 are stored and modified, as required, inorder to customize the operation of the implantable device 102 to suitthe needs of a particular patient. Such operating parameters define, forexample, pacing pulse amplitude, pulse duration, electrode polarity,rate, sensitivity, automatic features, arrhythmia detection criteria,and the amplitude, waveshape and vector of each shocking pulse to bedelivered to the patient's heart 106 within each respective tier oftherapy. With memory 660, the ICTD 102 is able to sense and store arelatively large amount of data (e.g., from the data acquisition system652), which may transmitted to the external network of knowledge workersfor subsequent analysis.

Operating parameters of the ICTD 102 may be non-invasively programmedinto the memory 660 through a telemetry circuit 664 in telemetriccommunication with an external device, such as a programmer 110 or localtransceiver 112. The telemetry circuit 664 advantageously allowsintracardiac electrograms and status information relating to theoperation of the device 102 (as contained in the microcontroller 620 ormemory 660) to be sent to the external devices.

The ICTD 100 can further include one or more physiologic sensors 670,commonly referred to as “rate-responsive” sensors because they aretypically used to adjust pacing stimulation rate according to theexercise state of the patient. However, the physiological sensor 670 mayfurther be used to detect changes in cardiac output, changes in thephysiological condition of the heart, or diurnal changes in activity(e.g., detecting sleep and wake states, detecting position or posturalchanges, etc.). Accordingly, the microcontroller 620 responds byadjusting the various pacing parameters (such as rate, AV Delay, V-VDelay, etc.) at which the atrial and ventricular pulse generators, 622and 624, generate stimulation pulses. While shown as being includedwithin the device 102, it is to be understood that the physiologicsensor 670 may also be external to the device 102, yet still beimplanted within or carried by the patient. Examples of physiologicsensors that may be implemented in device 102 include known sensorsthat, for example, sense respiration rate and/or minute ventilation, pHof blood, ventricular gradient, and so forth.

The ICTD 102 additionally includes a battery 676 that provides operatingpower to all of circuits shown in FIG. 2. If the device 102 isconfigured to deliver pacing or shocking therapy, the battery 676 iscapable of operating at low current drains for long periods of time(e.g., preferably less than 10 μA), and is capable of providinghigh-current pulses (for capacitor charging) when the patient requires ashock pulse (e.g., preferably, in excess of 2 A, at voltages above 2 V,for periods of 10 seconds or more). The battery 676 also desirably has apredictable discharge characteristic so that elective replacement timecan be detected. As one example, the device 102 employs lithium/silvervanadium oxide batteries.

The ICTD 102 can further include magnet detection circuitry (not shown),coupled to the microcontroller 620, to detect when a magnet is placedover the device 102. A magnet may be used by a clinician to performvarious test functions of the device 102 and/or to signal themicrocontroller 620 that the external programmer is in place to receiveor transmit data to the microcontroller 620 through the telemetrycircuits 664.

The ICTD 102 further includes an impedance measuring circuit 678 that isenabled by the microcontroller 620 via a control signal 680. Uses for animpedance measuring circuit 678 include, but are not limited to, leadimpedance surveillance during the acute and chronic phases for properlead positioning or dislodgement; detecting operable electrodes andautomatically switching to an operable pair if dislodgement occurs;measuring respiration or minute ventilation; measuring thoracicimpedance for determining shock thresholds; detecting when the devicehas been implanted; measuring stroke volume; and detecting the openingof heart valves, etc. The impedance measuring circuit 678 isadvantageously coupled to the switch 626 so that any desired electrodemay be used.

In the case where the device 102 is intended to operate as animplantable cardioverter/defibrillator (ICD) device, it detects theoccurrence of an arrhythmia, and automatically applies an appropriateelectrical shock therapy to the heart aimed at terminating the detectedarrhythmia. To this end, the microcontroller 620 further controls avoltage delivery circuit or shock circuit 682 by way of a control signal684. The shocking circuit 682 generates shocking pulses of low (up to0.5 Joules), moderate (0.5-10 Joules), or high energy (11 to 40 Joules),as controlled by the microcontroller 620. Such shocking pulses areapplied to the patient's heart 106 through at least two shockingelectrodes, and as shown in this implementation, selected from the leftatrial coil electrode 508, the RV coil electrode 514, and/or the SVCcoil electrode 516. As noted above, the housing 600 may act as an activeelectrode in combination with the RV coil electrode 514, or as part of asplit electrical vector using the SVC coil electrode 516 or the leftatrial coil electrode 508 (i.e., using the RV electrode as a commonelectrode).

Cardioversion shocks are generally considered to be of low to moderateenergy level (so as to minimize pain felt by the patient), and/orsynchronized with an R-wave and/or pertaining to the treatment oftachycardia. Defibrillation shocks are generally of moderate to highenergy level (i.e., corresponding to thresholds in the range of 5-40Joules), delivered asynchronously (since R-waves may be toodisorganized), and pertaining exclusively to the treatment offibrillation. Accordingly, the microcontroller 620 is capable ofcontrolling the synchronous or asynchronous delivery of the shockingpulses.

The ICTD 102 is further designed with the ability to supporthigh-frequency wireless communication, typically in the radio frequency(RF) range. The ICTD 102 is equipped with a high-frequency transceiver692 and a diplexer 694. High-frequency signals received by a dedicatedantenna 696, or via leads 108, are passed to the transceiver 692directly, or via diplexer 694. The high-frequency transceiver 692 may beconfigured to operate on one or a few frequencies. Alternatively, thetransceiver 692 may include a tuner 696 that tunes to variousfrequencies when attempting to establish communication links with theexternal communication device (e.g., programmer, local transceiver,etc.).

In one implementation, the high-frequency circuitry may be containedwithin a secondary, isolated casing 690 to enable handling ofhigh-frequency signals in isolation from the cardiac therapy circuitry.In this manner, the high-frequency signals can be safely received andtransmitted, thereby improving telemetry communication, withoutadversely disrupting operation of the other device circuitry.

Exemplary Computing Device

FIG. 7 shows an exemplary computing device 700 employed in the computingsystems of the cardiac therapy network architecture 100. It includes aprocessing unit 702 and memory 704. Memory 704 includes both volatilememory 706 (e.g., RAM) and non-volatile memory 708 (e.g., ROM, EEPROM,Flash, disk, optical discs, persistent storage, etc.). An operatingsystem and various application programs 710 are stored in non-volatilememory 708. When a program is running, various instructions are loadedinto volatile memory 706 and executed by processing unit 702. Examplesof possible applications that may be stored and executed on thecomputing device include the knowledge worker specific applications 206shown in FIG. 2.

The computing device 700 may further be equipped with a network I/Oconnection 720 to facilitate communication with a network. The networkI/O 720 may be a wire-based connection (e.g., network card, modem, etc.)or a wireless connection (e.g., RF transceiver, Bluetooth device, etc.).The computing device 700 may also include a user input device 722 (e.g.,keyboard, mouse, stylus, touch pad, touch screen, voice recognitionsystem, etc.) and an output device 724 (e.g., monitor, LCD, speaker,printer, etc.).

Various aspects of the methods and systems described throughout thisdisclosure may be implemented in computer software or firmware ascomputer-executable instructions. When executed, these instructionsdirect the computing device (alone, or in concert with other computingdevices of the system) to perform various functions and tasks thatenable the cardiac therapy network architecture 100.

Communication Protocol

One feature of the network architecture is an improved transmissionrange between the ICTD 102 and an external device such as the offlineprogrammer 110, the local transceiver 112, and/or programmer 116. Longrange telemetry allows communication with implanted medical devices atdistances greater than conventional “wand telemetry” of a few inches.Longer range telemetry is made possible by employing high-frequencysignals, such as RF signals. However, longer range telemetry introducesa challenge regarding how to establish communication with one or moreICTDs 102 at distances larger than several inches.

To address this challenge, the network architecture contemplates atechnique for interrogating one or more ICTDs that might be within rangeof an external device for purposes of establishing a communication link.Once established, the devices can use the link to exchange data anddownload programming parameters. The interrogation and communicationlinks are conducted over more than one allocated frequency band tosupport communication with multiple implantable devices.

FIG. 8 shows an exemplary ICTD 102 and an external communication device800 to illustrate how the communication device 800 interrogates an ICTD102 to establish a communication link. The external device 800 isequipped with a transceiver 802 that is capable of sending and receivingsignals over a wide range of frequencies, such as broadband RF signals.A tuner 804 is provided to tune to these different frequencies. Theexternal communication device 800 may be implemented in any number ofways, including as a programmer 110, as a local transceiver 112, and soon.

The external device 800 is equipped with an interrogation/listening unit808. It generates an interrogation signal (designated as “IFF” in FIG.8) designed to invite any listening ICTDs to establish a communicationlink. The interrogation/listening unit 808 directs the tuner 804 to oneor more frequencies within a set of possible interrogating frequencies.At each frequency, the transceiver 802 dispatches the interrogationsignal.

The ICTD-based transceiver 692 listens for the interrogation signal. Inone implementation, the ICTD transceiver 692 is designed to listen atone frequency within the possible range of interrogating frequencies,although more sophisticated transceivers may be configured to listenover a range of frequencies. When the ICTD receives the interrogationsignal, the ICTD-based transceiver 692 transmits a reply at a responsefrequency within a set of possible response frequencies. The reply maybe in the form of a device identification code (designated as “ID” inFIG. 8), or some other message. The reply may be transmitted at apre-selected frequency or at any one of numerous frequencies within theset of response frequencies. The set of interrogating frequencies andthe set of response frequencies may overlap or be mutually exclusive.

The interrogation/listening unit 808 listens for the reply from the ICTDtransceiver 692 over the response frequencies. The unit 808 listens fora predetermined response time interval triggered by transmission of theinterrogation signal. If no reply is detected within the time interval,the interrogation/listening unit 808 retransmits the interrogationsignal and restarts the interval. On the other hand, when the unit 808detects a reply, it commands the ICTD to tune to a designated frequencychannel to facilitate ongoing communication between the ICTD 102 and theexternal device 800. The frequency assigned to the ICTD is listed in theassigned frequency record 810 and associated with the ICTD. Uponreceiving this command, the ICTD-based tuner 696 tunes the transceiver692 to the designated channel.

From this point, the ICTD and external device can channel hop to otherfrequencies. According to one aspect, the ICTD and external device areconfigured to channel hop among frequencies more than once duringcommunication of information (e.g., one segment or bit of information).The channel hopping confers the advantage of greater tolerance toexternally-generated electromagnetic interference. This is based on theassumption that interference is less likely to occur in separatedfrequency bands than in one continuous band. Each information symbol maybe encoded as two separated frequencies to take advantage of thedecreased probability of interference.

FIG. 9 shows a process 900 for establishing a communication link betweenthe ICTD 102 and the external device 800. Aspects of this process may beimplemented in hardware, firmware, or software, or a combinationthereof. The process 900 is accomplished by operations performed at theICTD 102 and the external device 800. To illustrate which devicesperform which operations, the various operations are depicted as blocksarranged beneath headings identifying the devices that generally performthe operations.

At block 902, the external device 800 selects frequency ranges fortransmitting and receiving signals used in establishment ofcommunication with the ICTD. The selected transmission range encompassesan interrogating frequency to which the ICTD 102 is tuned to receive anyinterrogation signal from the external device 800. The selectedreceiving range of frequencies includes a response frequency at whichthe ICTD 102 is expected to return a reply to the interrogation signal.The transmission and receiving ranges may cover the same frequencies, oroverlap so that common frequencies are used in both transmission andreception, or be mutually exclusive bands of frequencies with no commonfrequency.

At block 904, the interrogation/listening unit 808 directs transceiver802 to transmit the interrogation code IFF at one or more of theinterrogating frequencies. According to one possible implementation, thetransceiver 802 transmits the interrogation signal on multiple or allinterrogating frequencies, either randomly or in a prescribed order. Theexternal device 800 then begins listening to one or more responsefrequencies for a reply from the ICTD 102 (block 906). It listens for apredetermined response time interval.

Meanwhile, at block 910, the ICTD 102 is listening at one or morefrequencies for the interrogation code. Depending upon power resources,the listening may be continuous or intermittent. Once the interrogationcode is detected, the ICTD 102 optionally delays for a random timeperiod within the response time interval (block 912) and then transmitsa reply at one of the response frequencies (block 914). The random delayallows the external device to listen for multiple ICTDs. That is, ifmultiple ICTDs respond to the same interrogation code on the sameresponse frequency, the random delays separate the replies allowing themto be received at the external device 800. The replies may be in theform of device identification codes so that the external device canidentify the one or more ICTDs.

The external device 800 listens for any reply over one or more receivingfrequencies for a predetermined response time interval (blocks 906, 920,922). If no reply is received, the external device continues listeninguntil the response interval lapses (i.e., the loop including block 906,the “no” branch from block 920, and the “no” branch from block 922). Ifno reply is received within the response interval, the external device902 retransmits the interrogation code (i.e., the “yes” branch fromblock 922 to block 904).

If a reply is received within the response interval (i.e., the “yes”branch from block 920), the external device 800 assigns a communicationchannel to the ICTD 102 (block 924). The external device 800 records thechannel in the log 810 in association with the specific ICTD, andtransmits the designated channel to the ICTD (block 926). The ICTD andexternal device employ the designated channel for ongoing communication.

Once a particular ICTD and external device are communicating on theassigned channel, that communication channel may be used to downloaddata from the ICTD, query the ICTD, or submit programming instructionsto the ICTD. The communicating devices may conduct all continuingcommunication on the assigned channel, or hop to other frequencies usingknown frequency hopping techniques. Accordingly, at block 928, the ICTDand external device may optionally channel hop to multiple frequenciesmultiple times during communication of information.

At this point, the process flow returns to block 902 to select the sameor a new set of frequencies with the intention of interrogating andestablishing communication with another ICTD.

FIG. 10 illustrates the communication protocol for establishing linksbetween the external device 800 and multiple ICTDs 102(1), 102(2), . . ., 102(M). The external device 800 transmits an interrogation code IFFover one or more interrogating frequencies. The ICTDs 102(1)-(M) aretuned or configured to listen to the same or different ones of theseinterrogating frequencies. When an ICTD receives the interrogation code,it returns a reply on a different frequency being monitored by theexternal device 800. The reply includes an identification code ID thatuniquely identifies the implantable device D₁, D₂, . . . , D_(M).

The ICTDs 102(1)-(M) can be configured to transmit the replies after arandom delay period. For instance, ICTD 102(1) might reply at randomtime t₁, which is within the response time interval T₀ (i.e., 0<t₁<T₀).Similarly, ICTDs 102(2), . . . , 102(M) reply at random times t₂, t_(M),which are likely to be different from one another, but still fall withinthe response time interval T_(o). In this manner, if multiple ICTDslisten to the same frequency and respond to the same interrogation code,there is an increased probability that the ICTDs will reply at differenttimes so that the external device receives all replies.

As the external device 800 receives the replies, it assigns differentcommunication channels to the ICTDs 102(1)-(M). For instance, channelCC1 is assigned for communication between ICTD 102(1) and the externaldevice 800; channel CC2 is assigned for communication between the ICTD102(2) and the external device 800; and channel CCM is assigned forcommunication between ICTD 102(M) and the external device 800.

The assigned communication channels are recorded in the log 810 inassociation with the ICTDs identification codes so that continuingcommunication between the ICTDs and the external devices are handled ina one-to-one link. This ensures that data read from individual ICTDs areassociated with the appropriate patients and any programminginstructions are delivered to the appropriate ICTDs, thereby preventingany situation where one ICTD is programmed to deliver therapy intendedfor another patient.

Exemplary Packaging Design

FIG. 11 shows an exemplary ICTD 102 that is equipped with additionalhigh-frequency packaging and circuitry to support long range telemetry.Generally, ICTD 102 is designed with a hermetically shielded can 600 toprevent electromagnetic interference (EMI) from disrupting operation ofthe sensing and/or stimulation circuitry. The can 600 employs one ormore filters to block high-frequency transmissions (e.g., radiofrequencies) and other sources of EMI (e.g., automobile engines). As anexample, the filters typically attenuate signals significantly, above 1MHz. Thus, the can 600 prevents penetration of high frequencies andtries to limit communication to the low frequency ranges of less than200 KHz.

The ICTD 102 has a header 1102 that holds the connection terminals forleads 108(1)-(3). The header is commonly formed of an epoxy materialmounted on can 600, which is commonly formed of a conducting materialsuch as titanium. In this construction, the high-frequency circuitry iscontained within a separate frequency-isolated packaging region 1104adjacent to the header 1102. The region 1104 is defined in part by wall690, which is constructed, for example, of a conducting material such astitanium. The high-frequency packaging region 1104 can be thought of asa separate can or chamber that isolates the RF components from the maincircuitry. The dual-can design enables the ICTD to handle high-frequencysignals carrying data and control information in one can of the devicewithout disrupting operation of the main circuitry in the second can orchamber of the device.

The transceiver 692 and diplexer 694 are positioned within thehigh-frequency packaging region 1104. Signals received from a lead 108or a dedicated antenna 696 are passed through an unfiltered feed-through1106 to a diplexer 694. The diplexer 694 allows two signals of differentfrequencies to be transmitted along the same conductor and separates thesignal frequencies onto two different connections. In the illustratedimplementation, the diplexer 694 is designed to direct RF signals to theRF transceiver 692 and the electrocardiograph (ECG) signals to the maincircuitry in the main chamber.

The diplexer's first connection 1108 leads to a feed-through 1110 intothe ICTD circuitry within the main chamber. The diplexer 694 filtersthis first connection to pass low frequencies of the ECG signal. Highfrequencies are blocked and therefore do not interfere with the sensingof the ECG.

A second connection 1112 on the diplexer 694 connects to the transceiver692. The filter on this connection is tuned to pass a band of highfrequencies. The transceiver is capable of receiving and transmittinghigh-frequency signals, such as those found in the radio frequencyrange. As one example range, the transceiver handles signals within 200to 900 MHz. Low frequency signals, such as the ECG, on connection 1112are blocked. The transceiver 692 extracts any codes, data and/or controlinstructions from the carrier frequency modulation and passes theinformation to the ICTD circuitry via connections 1114 and afeed-through 1116. The feed-through 1116 can be filtered to prevent anyhigh-frequency components from entering the main circuit chamber. Themetal shield encompassing the high-frequency chamber 1104 blocksspurious signals emanating from the RF transceiver 692 from interferingwith the sensing and pacing functions of the main circuitry. Power issupplied to the transceiver 692 and diplexer 694 from the battery in themain circuitry chamber via the feed-throughs 1110 and 1116.

The dual-chamber design provides optimal isolation. With the diplexer,dual enclosure regions, and filtered feed-throughs, the design isolatesthe main monitoring/stimulating circuitry from RF interference emanatingfrom the diplexer or transceiver, while simultaneously allowinglong-range RF telemetry communication. Additionally, the design allowsthe leads to be used as both stimulation/sensing leads and as a radiofrequency (RF) antenna, without causing interference to the monitoringand/or stimulation functions.

In the illustrated implementation, the high-frequency region 1104 isshown adjacent to header 1102 and above the main circuit chamber,encapsulated by the outer can wall of the device and the interior wall690. It is noted that the region 1104 may be located in any number ofplaces. It may be, for example, implemented as an isolated cavitycontained entirely within the main circuit chamber. Alternatively, itmay be constructed external to the ICTD 102, but employ part of theexterior can 600 to define a portion of the region. Another possibleimplementation is to construct the high-frequency region as a separateimplantable can that is in communication with the ICTD, but implantedapart from the ICTD 102.

The antenna for transmitting and receiving the high-frequency datasignals may be implemented in a number of ways. One approach is to useone or more of the leads 108(1)-(3) as the antenna. Another approach isto employ a dedicated antenna positioned within the header region 1102.A third approach is to employ a dedicated antenna that extends beyondthe header region 1102. Still another approach is to integrate theantenna into the can 600.

CONCLUSION

Although the invention has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described. Rather,the specific features and acts are disclosed as exemplary forms ofimplementing the claimed invention.

1. A method comprising: receiving data from an implantable medicaldevice at a data integrator configured to accumulate the data; storingthe data in a central repository communicatively connected to the dataintegrator; evaluating the data for accuracy and completeness at aprocessing system commutatively connected to the central repository;processing the data according to a knowledge worker specific applicationthat is specifically tailored to place the data into condition for afirst knowledge worker; transmitting at least a portion of the data fromthe central repository to a distribution/presentation system configuredto serve the data according to protocols and formats of a computersystem at a first location associated with a first knowledge worker;transmitting the data from the distribution/presentation system to thefirst location according to the protocols and formats of the computersystem at the first location; further processing the data at the firstlocation by the computer system, the further processing specific to ause of the data by the first knowledge worker; generating at the firstlocation additional data that is useful to at least one of a patientassociated with the implantable medical device or a second knowledgeworker; and transmitting the additional data from the first location toa second location associated with the second knowledge worker.
 2. Amethod as recited in claim 1, and further comprising generating anotification to the patient associated with the implantable medicaldevice in response to the processing of the data.
 3. The method of claim2, wherein the generating the notification is performed by the secondknowledge worker.
 4. The method of claim 1, and further comprisinggenerating a notification from the first location to the second locationin response to the processing of the data.
 5. The method of claim 1wherein transmitting the processed data comprises transmitting theprocessed data directly from the first location to the second location.6. The method of claim 1, wherein transmitting the processed datacomprises transmitting the processed data from the first location to thesecond location through the central repository.
 7. The method of claim1, wherein the first knowledge worker comprises a clinical group, thesecond knowledge worker comprises a healthcare provider, and theprocessing the data at the first location comprises identifying data forinclusion in patient populations that can be studied and analyzed. 8.The method of claim 1, wherein the first knowledge worker comprises amanufacture of the implantable medical device, the portion of the datacomprises data pertaining to operation of the implantable medicaldevice, and the additional data comprises data useful to develop bettertechnologies for future generations of implantable medical devices.
 9. Asystem comprising: means for receiving data from an implantable medicaldevice and storing it in a central repository; means for evaluating theaccuracy and completeness of the data; means for generating at least twodifferent data packages, each data package comprising different portionsof the data; means for transmitting at least a first data package fromthe central repository to a first location associated with a firstknowledge worker, the first data package served to a computer system atthe first location according to protocols and formats desired by thecomputer system; means for processing the first data package at thefirst location by a computer system, the processing specific to a use ofthe first data package by the first knowledge worker; means forgenerating, at the first location, additional data that is useful to atleast one of a patient associated with the implantable medical device ora second knowledge worker; and means for transmitting the additionaldata from the first location to a second location associated with thesecond knowledge worker.
 10. The system of claim 9, and furthercomprising means for generating a notification to the patient associatedwith the implantable medical device in response to the processing of thedata.
 11. The system of claim 10, wherein the means for generating anotification comprises means for generating the notification by thesecond knowledge worker.
 12. The system of claim 9, and furthercomprising means for generating a notification from the first locationto the second location in response to the processing of the data. 13.The system of claim 9, wherein the means for transmitting the processeddata comprises means for transmitting the processed data directly fromthe first location to the second location.
 14. The system of claim 9,wherein the means for transmitting the processed data comprises meansfor transmitting the processed data from the first location to thesecond location through the central repository.
 15. The system of claim9, wherein the first knowledge worker comprises a clinical group, thesecond knowledge worker comprises a healthcare provider, and theprocessing the data at the first location comprises identifying data forinclusion in patient populations that can be studied and analyzed. 16.The system of claim 9, wherein the first knowledge worker comprises aclinical scientist, the data package includes heart data but does notinclude patient identification information, and the additional datacomprises the data useful to gain a better understanding of howimplantable medical devices operate in general.
 17. A method comprising:receiving data from an implantable medical device at a centralrepository; processing the data by a processing system in communicationwith the central repository according to a knowledge worker specificapplication that is specifically tailored to create a data package thatincludes a portion of the data which is of interest to a first knowledgeworker; storing the data package in the central repository; transmittingthe data package from the central repository to adistribution/presentation system in communication with the centralrepository; serving the data package from the distribution/presentationsystem to a first location associated with the first knowledge workeraccording to protocols and formats of a computer system at the firstlocation; performing further processing of the data package at the firstlocation to obtain data results and to generate instructionscorresponding to the data results; and transmitting the instructionsfrom the first location to a second location associated with a secondknowledge worker.
 18. The method of claim 17, and further comprisinggenerating a notification from the first location to the second locationin response to the processing of the data.
 19. The method of claim 17,wherein transmitting the processed data comprises transmitting theprocessed data directly from the first location to the second location.20. The method of claim 17, wherein transmitting the processed datacomprises transmitting the processed data from the first location to thesecond location through the central repository.
 21. The method of claim17, wherein the first knowledge worker comprises a clinical group, thesecond knowledge worker comprises a healthcare provider, and theinstructions comprises instructions to include or exclude a patient in apatient population that can be studied and analyzed.
 22. The method ofclaim 17, wherein the first knowledge worker comprises a health-careworker, the portion of the data includes electrocardiogram data (ECG)and patient identification information for a patient in which theimplantable medical device is implanted, and the instructions comprisean improved therapy for the patient.